Field of the Invention
Exemplary embodiments of the present invention relate to a lumbar support, and more particularly, to a 4-way lumbar support capable of automatically adjusting a vertical position and an amount of forward protrusion of a curved part of a lumbar plate, which is provided in a vehicle seat back, using respective motors.
Description of the Related Art
In general, a driver seat, an occupant seat, and seats as other occupant seats, which are installed in front of and behind a vehicle interior, have various comfort devices for convenience of occupants.
The comfort devices have a sliding function of adjusting a seat cushion by the forward and backward pushing/pulling of the seat cushion, a reclining function of adjusting the inclination of a seat back corresponding to the back of the seat, according to the body types of occupants, and a seat height adjustment function of adjusting the height of the seat cushion so as to be suitable for the body sizes of occupants.
In addition, in order to basically cope with a change in seating posture of an occupant during long-time driving, a cushion for comfortably surrounding the back of the occupant and a lumbar support for comfortably supporting the lumbar have been adopted within the seat back.
In particular, there is applied a 4-way lumbar support capable of adjusting an amount of forward curvature of a lumbar plate, which is provided in the seat back to extend vertically along the back of the occupant and has elasticity, and the vertical curved position of the lumbar plate, so as to be suitable for the body type of the occupant using the lumbar plate.
In connection with the conventional lumbar support which is adjustable in four directions, Korean Patent Laid-open Publication No. 10-2007-0039774 discloses a structure that adjusts an amount of curvature and a curved position of a lumbar plate using a plurality of wires.
This method of using the wires may cause inconvenience for an occupant because the occupant has to basically adjust the amount of curvature and the curved position of the lumbar plate by operating a lever or dial connected to end portions of the wires.
In addition, the wires are stretched by a certain amount with the elapse of long time in the state in which a predetermined tensile force is applied to the wires. For this reason, it is difficult to secure an amount of curvature of the lumbar plate over a certain level in the state in which the wires are stretched.
Moreover, when a large load, such as the weight of an occupant generated by the rear-end collision of the vehicle, is applied to the lumbar plate in the method of using the wires, a connection portion between the lumbar plate and the wires may be damaged or even be destroyed due to the load applied to the lumbar plate from the occupant.
As an alternative to this, Korean Patent Laid-open Publication No. 1999-021067 discloses a structure that mechanically adjusts an amount of forward curvature of a lumbar plate using a rotating rod, which extends in a direction perpendicular to the lumbar plate and has a screw formed on one end thereof. However, such a structure is problematic in that the rotating rod has a limited length due to the thickness of the seat back in the forward and backward direction thereof, and thus the amount of forward curvature of the lumbar plate is limited to a certain level.    [Patent Document 0001] Korean Patent Laid-open Publication No. 10-2007-0039774    [Patent Document 0002] Korean Patent Laid-open Publication No. 1999-021067